Commit Graph

16205 Commits

Author SHA1 Message Date
Frederic Weisbecker
65f382fd0c context_tracking: Ground setup for static key use
Prepare for using a static key in the context tracking subsystem.
This will help optimizing the off case on its many users:

* user_enter, user_exit, exception_enter, exception_exit, guest_enter,
  guest_exit, vtime_*()

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
2013-08-14 17:12:46 +02:00
Frederic Weisbecker
d84d27a491 context_tracking: Remove full dynticks' hacky dependency on wide context tracking
Now that the full dynticks subsystem only enables the context tracking
on full dynticks CPUs, lets remove the dependency on CONTEXT_TRACKING_FORCE

This dependency was a hack to enable the context tracking widely for the
full dynticks susbsystem until the latter becomes able to enable it in a
more CPU-finegrained fashion.

Now CONTEXT_TRACKING_FORCE only stands for testing on archs that
work on support for the context tracking while full dynticks can't be
used yet due to unmet dependencies. It simulates a system where all CPUs
are full dynticks so that RCU user extended quiescent states and dynticks
cputime accounting can be tested on the given arch.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
2013-08-13 00:54:34 +02:00
Frederic Weisbecker
2e70933866 nohz: Only enable context tracking on full dynticks CPUs
The context tracking subsystem has the ability to selectively
enable the tracking on any defined subset of CPU. This means that
we can define a CPU range that doesn't run the context tracking
and another range that does.

Now what we want in practice is to enable the tracking on full
dynticks CPUs only. In order to perform this, we just need to pass
our full dynticks CPU range selection from the full dynticks
subsystem to the context tracking.

This way we can spare the overhead of RCU user extended quiescent
state and vtime maintainance on the CPUs that are outside the
full dynticks range. Just keep in mind the raw context tracking
itself is still necessary everywhere.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
2013-08-13 00:54:07 +02:00
Frederic Weisbecker
d65ec12127 context_tracking: Fix runtime CPU off-case
As long as the context tracking is enabled on any CPU, even
a single one, all other CPUs need to keep track of their
user <-> kernel boundaries cross as well.

This is because a task can sleep while servicing an exception
that happened in the kernel or in userspace. Then when the task
eventually wakes up and return from the exception, the CPU needs
to know if we resume in userspace or in the kernel. exception_exit()
get this information from exception_enter() that saved the previous
state.

If the CPU where the exception happened didn't keep track of
these informations, exception_exit() doesn't know which state
tracking to restore on the CPU where the task got migrated
and we may return to userspace with the context tracking
subsystem thinking that we are in kernel mode.

This can be fixed in the long term if we move our context tracking
probes on very low level arch fast path user <-> kernel boundary,
although even that is worrisome as an exception can still happen
in the few instructions between the probe and the actual iret.

Also we are not yet ready to set these probes in the fast path given
the potential overhead problem it induces.

So let's fix this by always enable context tracking even on CPUs
that are not in the full dynticks range. OTOH we can spare the
rcu_user_*() and vtime_user_*() calls there because the tick runs
on these CPUs and we can handle RCU state machine and cputime
accounting through it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
2013-08-13 00:40:44 +02:00
Frederic Weisbecker
5b206d48e5 vtime: Update a few comments
Update a stale comment from the old vtime era and document some
locking that might be non obvious.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
2013-08-13 00:40:44 +02:00
Frederic Weisbecker
2d854e5738 context_tracing: Fix guest accounting with native vtime
1) If context tracking is enabled with native vtime accounting (which
combo is useless except for dev testing), we call vtime_guest_enter()
and vtime_guest_exit() on host <-> guest switches. But those are stubs
in this configurations. As a result, cputime is not correctly flushed
on kvm context switches.

2) If context tracking runs but is disabled on some CPUs, those
CPUs end up calling __guest_enter/__guest_exit which in turn
call vtime_account_system(). We don't want to call this because we
run in tick based accounting for these CPUs.

Refactor the guest_enter/guest_exit code such that all combinations
finally work.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
2013-08-13 00:40:44 +02:00
Frederic Weisbecker
fbb00b568b sched: Consolidate open coded preemptible() checks
preempt_schedule() and preempt_schedule_context() open
code their preemptability checks.

Use the standard API instead for consolidation.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Alex Shi <alex.shi@intel.com>
Cc: Paul Turner <pjt@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
2013-08-13 00:40:43 +02:00
Ingo Molnar
ae920eb242 Merge branch 'fortglx/3.11/time' of git://git.linaro.org/people/jstultz/linux into timers/urgent
Pull small fix for v3.11 from John Stultz.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-08-12 18:08:23 +02:00
Ingo Molnar
365d8c001f Merge branch 'timers/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/urgent
Pull nohz fixes from Frederic Weisbecker.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-25 23:03:28 +02:00
Li Zhong
ca06416b2b nohz: fix compile warning in tick_nohz_init()
cpu is not used after commit 5b8621a68f

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2013-07-24 20:30:33 +02:00
Steven Rostedt
543487c7a2 nohz: Do not warn about unstable tsc unless user uses nohz_full
If the user enables CONFIG_NO_HZ_FULL and runs the kernel on a machine
with an unstable TSC, it will produce a WARN_ON dump as well as taint
the kernel. This is a bit extreme for a kernel that just enables a
feature but doesn't use it.

The warning should only happen if the user tries to use the feature by
either adding nohz_full to the kernel command line, or by enabling
CONFIG_NO_HZ_FULL_ALL that makes nohz used on all CPUs at boot up. Note,
this second feature should not (yet) be used by distros or anyone that
doesn't care if NO_HZ is used or not.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2013-07-24 20:30:33 +02:00
Linus Torvalds
b3a3a9c441 This contains fixes, optimizations and some clean ups
Some of the fixes need to go back to 3.10. They are minor, and deal mostly
 with incorrect ref counting in accessing event files.
 
 There was a couple of optimizations that should have perf perform a bit
 better when accessing trace events.
 
 And some various clean ups. Some of the clean ups are necessary to help
 in a fix to a theoretical race between opening a event file and
 deleting that event.
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Merge tag 'trace-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes and cleanups from Steven Rostedt:
 "This contains fixes, optimizations and some clean ups

  Some of the fixes need to go back to 3.10.  They are minor, and deal
  mostly with incorrect ref counting in accessing event files.

  There was a couple of optimizations that should have perf perform a
  bit better when accessing trace events.

  And some various clean ups.  Some of the clean ups are necessary to
  help in a fix to a theoretical race between opening a event file and
  deleting that event"

* tag 'trace-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Kill the unbalanced tr->ref++ in tracing_buffers_open()
  tracing: Kill trace_array->waiter
  tracing: Do not (ab)use trace_seq in event_id_read()
  tracing: Simplify the iteration logic in f_start/f_next
  tracing: Add ref_data to function and fgraph tracer structs
  tracing: Miscellaneous fixes for trace_array ref counting
  tracing: Fix error handling to ensure instances can always be removed
  tracing/kprobe: Wait for disabling all running kprobe handlers
  tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()
  tracing/syscall: Avoid perf_trace_buf_*() if sys_data->perf_events is empty
  tracing/function: Avoid perf_trace_buf_*() if event_function.perf_events is empty
  tracing: Typo fix on ring buffer comments
  tracing: Use trace_seq_puts()/trace_seq_putc() where possible
  tracing: Use correct config guard CONFIG_STACK_TRACER
2013-07-22 19:07:24 -07:00
Baruch Siach
53c0352042 sched_clock: Fix integer overflow
The expression '(1 << 32)' happens to evaluate as 0 on ARM, but
it evaluates as 1 on xtensa and x86_64. This zeros sched_clock_mask,
and breaks sched_clock().

Set the type of 1 to 'unsigned long long' to get the value we need.

Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-07-22 16:24:22 -07:00
Oleg Nesterov
e70e78e3c8 tracing: Kill the unbalanced tr->ref++ in tracing_buffers_open()
tracing_buffers_open() does trace_array_get() and then it wrongly
inrcements tr->ref again under trace_types_lock. This means that
every caller leaks trace_array:

	# cd /sys/kernel/debug/tracing/
	# mkdir instances/X
	# true < instances/X/per_cpu/cpu0/trace_pipe_raw
	# rmdir instances/X
	rmdir: failed to remove `instances/X': Device or resource busy

Link: http://lkml.kernel.org/r/20130719153644.GA18899@redhat.com

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-19 14:32:22 -04:00
Linus Torvalds
b7356abb9f Power management and ACPI fixes for 3.11-rc2
- Two cpufreq commits from the 3.10 cycle introduced regressions.
   The first of them was buggy (it did way much more than it needed
   to do) and the second one attempted to fix an issue introduced by
   the first one.  Fixes from Srivatsa S Bhat revert both.
 
 - If autosleep triggers during system shutdown and the shutdown
   callbacks of some device drivers have been called already, it may
   crash the system.  Fix from Liu Shuo prevents that from happening
   by making try_to_suspend() check system_state.
 
 - The ACPI memory hotplug driver doesn't clear its driver_data on
   errors which may cause a NULL poiter dereference to happen later.
   Fix from Toshi Kani.
 
 - The ACPI namespace scanning code should not try to attach scan
   handlers to device objects that have them already, which may confuse
   things quite a bit, and it should rescan the whole namespace branch
   starting at the given node after receiving a bus check notify event
   even if the device at that particular node has been discovered
   already.  Fixes from Rafael J Wysocki.
 
 - New ACPI video blacklist entry for a system whose initial backlight
   setting from the BIOS doesn't make sense.  From Lan Tianyu.
 
 - Garbage string output avoindance for ACPI PNP from Liu Shuo.
 
 - Two Kconfig fixes for issues introduced recently in the s3c24xx
   cpufreq driver (when moving the driver to drivers/cpufreq) from
   Paul Bolle.
 
 - Trivial comment fix in pm_wakeup.h from Chanwoo Choi.
 
 /
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Merge tag 'pm+acpi-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI fixes from Rafael Wysocki:
 "These are fixes collected over the last week, most importnatly two
  cpufreq reverts fixing regressions introduced in 3.10, an autoseelp
  fix preventing systems using it from crashing during shutdown and two
  ACPI scan fixes related to hotplug.

  Specifics:

   - Two cpufreq commits from the 3.10 cycle introduced regressions.
     The first of them was buggy (it did way much more than it needed to
     do) and the second one attempted to fix an issue introduced by the
     first one.  Fixes from Srivatsa S Bhat revert both.

   - If autosleep triggers during system shutdown and the shutdown
     callbacks of some device drivers have been called already, it may
     crash the system.  Fix from Liu Shuo prevents that from happening
     by making try_to_suspend() check system_state.

   - The ACPI memory hotplug driver doesn't clear its driver_data on
     errors which may cause a NULL poiter dereference to happen later.
     Fix from Toshi Kani.

   - The ACPI namespace scanning code should not try to attach scan
     handlers to device objects that have them already, which may
     confuse things quite a bit, and it should rescan the whole
     namespace branch starting at the given node after receiving a bus
     check notify event even if the device at that particular node has
     been discovered already.  Fixes from Rafael J Wysocki.

   - New ACPI video blacklist entry for a system whose initial backlight
     setting from the BIOS doesn't make sense.  From Lan Tianyu.

   - Garbage string output avoindance for ACPI PNP from Liu Shuo.

   - Two Kconfig fixes for issues introduced recently in the s3c24xx
     cpufreq driver (when moving the driver to drivers/cpufreq) from
     Paul Bolle.

   - Trivial comment fix in pm_wakeup.h from Chanwoo Choi"

* tag 'pm+acpi-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / video: ignore BIOS initial backlight value for Fujitsu E753
  PNP / ACPI: avoid garbage in resource name
  cpufreq: Revert commit 2f7021a8 to fix CPU hotplug regression
  cpufreq: s3c24xx: fix "depends on ARM_S3C24XX" in Kconfig
  cpufreq: s3c24xx: rename CONFIG_CPU_FREQ_S3C24XX_DEBUGFS
  PM / Sleep: Fix comment typo in pm_wakeup.h
  PM / Sleep: avoid 'autosleep' in shutdown progress
  cpufreq: Revert commit a66b2e to fix suspend/resume regression
  ACPI / memhotplug: Fix a stale pointer in error path
  ACPI / scan: Always call acpi_bus_scan() for bus check notifications
  ACPI / scan: Do not try to attach scan handlers to devices having them
2013-07-19 09:59:06 -07:00
Oleg Nesterov
a644a7e958 tracing: Kill trace_array->waiter
Trivial. trace_array->waiter has no users since 6eaaa5d5
"tracing/core: use appropriate waiting on trace_pipe".

Link: http://lkml.kernel.org/r/20130719142036.GA1594@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-19 10:56:02 -04:00
Oleg Nesterov
cd458ba9d5 tracing: Do not (ab)use trace_seq in event_id_read()
event_id_read() has no reason to kmalloc "struct trace_seq"
(more than PAGE_SIZE!), it can use a small buffer instead.

Note: "if (*ppos) return 0" looks strange and even wrong,
simple_read_from_buffer() handles ppos != 0 case corrrectly.

And it seems that almost every user of trace_seq in this file
should be converted too. Unless you use seq_open(), trace_seq
buys nothing compared to the raw buffer, but it needs a bit
more memory and code.

Link: http://lkml.kernel.org/r/20130718184712.GA4786@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:33 -04:00
Oleg Nesterov
7710b63995 tracing: Simplify the iteration logic in f_start/f_next
f_next() looks overcomplicated, and it is not strictly correct
even if this doesn't matter.

Say, FORMAT_FIELD_SEPERATOR should not return NULL (means EOF)
if trace_get_fields() returns an empty list, we should simply
advance to FORMAT_PRINTFMT as we do when we find the end of list.

1. Change f_next() to return "struct list_head *" rather than
   "ftrace_event_field *", and change f_show() to do list_entry().

   This simplifies the code a bit, only f_show() needs to know
   about ftrace_event_field, and f_next() can play with ->prev
   directly

2. Change f_next() to not play with ->prev / return inside the
   switch() statement. It can simply set node = head/common_head,
   the prev-or-advance-to-the-next-magic below does all work.

While at it. f_start() looks overcomplicated too. I don't think
*pos == 0 makes sense as a separate case, just change this code
to do "while" instead of "do/while".

The patch also moves f_start() down, close to f_stop(). This is
purely cosmetic, just to make the locking added by the next patch
more clear/visible.

Link: http://lkml.kernel.org/r/20130718184710.GA4783@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:32 -04:00
Steven Rostedt (Red Hat)
8f76899339 tracing: Add ref_data to function and fgraph tracer structs
The selftest for function and function graph tracers are defined as
__init, as they are only executed at boot up. The "tracer" structs
that are associated to those tracers are not setup as __init as they
are used after boot. To stop mismatch warnings, those structures
need to be annotated with __ref_data.

Currently, the tracer structures are defined to __read_mostly, as they
do not really change. But in the future they should be converted to
consts, but that will take a little work because they have a "next"
pointer that gets updated when they are registered. That will have to
wait till the next major release.

Link: http://lkml.kernel.org/r/1373596735.17876.84.camel@gandalf.local.home

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Reported-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:31 -04:00
Alexander Z Lam
f77d09a384 tracing: Miscellaneous fixes for trace_array ref counting
Some error paths did not handle ref counting properly, and some trace files need
ref counting.

Link: http://lkml.kernel.org/r/1374171524-11948-1-git-send-email-azl@google.com

Cc: stable@vger.kernel.org # 3.10
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:30 -04:00
Alexander Z Lam
609e85a70b tracing: Fix error handling to ensure instances can always be removed
Remove debugfs directories for tracing instances during creation if an error
occurs causing the trace_array for that instance to not be added to
ftrace_trace_arrays. If the directory continues to exist after the error, it
cannot be removed because the respective trace_array is not in
ftrace_trace_arrays.

Link: http://lkml.kernel.org/r/1373502874-1706-2-git-send-email-azl@google.com

Cc: stable@vger.kernel.org # 3.10
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:30 -04:00
Masami Hiramatsu
a232e270dc tracing/kprobe: Wait for disabling all running kprobe handlers
Wait for disabling all running kprobe handlers when a kprobe
event is disabled, since the caller, trace_remove_event_call()
supposes that a removing event is disabled completely by
disabling the event.
With this change, ftrace can ensure that there is no running
event handlers after disabling it.

Link: http://lkml.kernel.org/r/20130709093526.20138.93100.stgit@mhiramat-M0-7522

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:29 -04:00
Oleg Nesterov
cd92bf61d6 tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()
Every perf_trace_buf_prepare() caller does
WARN_ONCE(size > PERF_MAX_TRACE_SIZE, message) and "message" is
almost the same.

Shift this WARN_ONCE() into perf_trace_buf_prepare(). This changes
the meaning of _ONCE, but I think this is fine.

	- 4947014 2932448 10104832  17984294  1126b26 vmlinux
	+ 4948422 2932448 10104832  17985702  11270a6 vmlinux

on my build.

Link: http://lkml.kernel.org/r/20130617170211.GA19813@redhat.com

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:28 -04:00
Oleg Nesterov
421c7860c6 tracing/syscall: Avoid perf_trace_buf_*() if sys_data->perf_events is empty
perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL)
make no sense if hlist_empty(head). Change perf_syscall_enter/exit()
to check sys_data->{enter,exit}_event->perf_events beforehand.

Link: http://lkml.kernel.org/r/20130617170207.GA19806@redhat.com

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:28 -04:00
Oleg Nesterov
b8ebfd3f71 tracing/function: Avoid perf_trace_buf_*() if event_function.perf_events is empty
perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL)
make no sense if hlist_empty(head). Change perf_ftrace_function_call()
to check event_function.perf_events beforehand.

Link: http://lkml.kernel.org/r/20130617170204.GA19803@redhat.com

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:27 -04:00
zhangwei(Jovi)
d611851b42 tracing: Typo fix on ring buffer comments
There have some mismatch between comments with
real function name, update it.

This patch also add some missed function arguments
description.

Link: http://lkml.kernel.org/r/51E3B3B2.4080307@huawei.com

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:31:26 -04:00
zhangwei(Jovi)
146c3442f2 tracing: Use trace_seq_puts()/trace_seq_putc() where possible
For string without format specifiers, use trace_seq_puts()
or trace_seq_putc().

Link: http://lkml.kernel.org/r/51E3B3AC.1000605@huawei.com

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
[ fixed a trace_seq_putc(s, " ") to trace_seq_putc(s, ' ') ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-18 21:30:36 -04:00
Linus Torvalds
7a62711aac Driver core patches for 3.11-rc2
Here are some driver core patches for 3.11-rc2.  They aren't really
 bugfixes, but a bunch of new helper macros for drivers to properly
 create attribute groups, which drivers and subsystems need to fix up a
 ton of race issues with incorrectly creating sysfs files (binary and
 normal) after userspace has been told that the device is present.
 
 Also here is the ability to create binary files as attribute groups, to
 solve that race condition, which was impossible to do before this, so
 that's my fault the drivers were broken.
 
 The majority of the .c changes is indenting and moving code around a
 bit.  It affects no existing code, but allows the large backlog of 70+
 patches that I already have created to start flowing into the different
 subtrees, instead of having to live in my driver-core tree, causing
 merge nightmares in linux-next for the next few months.
 
 These were finalized too late for the -rc1 merge window, which is why
 they were didn't make that pull request, testing and review from others
 didn't happen until a few weeks ago, and then there's the whole
 distraction of the past few days, which prevented these from getting to
 you sooner, sorry about that.
 
 Oh, and there's a bugfix for the documentation build warning in here as
 well.  All of these have been in linux-next this week, with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core patches from Greg KH:
 "Here are some driver core patches for 3.11-rc2.  They aren't really
  bugfixes, but a bunch of new helper macros for drivers to properly
  create attribute groups, which drivers and subsystems need to fix up a
  ton of race issues with incorrectly creating sysfs files (binary and
  normal) after userspace has been told that the device is present.

  Also here is the ability to create binary files as attribute groups,
  to solve that race condition, which was impossible to do before this,
  so that's my fault the drivers were broken.

  The majority of the .c changes is indenting and moving code around a
  bit.  It affects no existing code, but allows the large backlog of 70+
  patches that I already have created to start flowing into the
  different subtrees, instead of having to live in my driver-core tree,
  causing merge nightmares in linux-next for the next few months.

  These were finalized too late for the -rc1 merge window, which is why
  they were didn't make that pull request, testing and review from
  others didn't happen until a few weeks ago, and then there's the whole
  distraction of the past few days, which prevented these from getting
  to you sooner, sorry about that.

  Oh, and there's a bugfix for the documentation build warning in here
  as well.  All of these have been in linux-next this week, with no
  reported problems"

* tag 'driver-core-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  driver-core: fix new kernel-doc warning in base/platform.c
  sysfs: use file mode defines from stat.h
  sysfs: add more helper macro's for (bin_)attribute(_groups)
  driver core: add default groups to struct class
  driver core: Introduce device_create_groups
  sysfs: prevent warning when only using binary attributes
  sysfs: add support for binary attributes in groups
  driver core: device.h: add RW and RO attribute macros
  sysfs.h: add BIN_ATTR macro
  sysfs.h: add ATTRIBUTE_GROUPS() macro
  sysfs.h: add __ATTR_RW() macro
2013-07-18 12:48:40 -07:00
Greg Kroah-Hartman
b9b3259746 sysfs.h: add __ATTR_RW() macro
A number of parts of the kernel created their own version of this, might
as well have the sysfs core provide it instead.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-16 10:57:36 -07:00
zhangwei(Jovi)
991821c86c tracing: Use correct config guard CONFIG_STACK_TRACER
We should use CONFIG_STACK_TRACER to guard readme text
of stack tracer related file, not CONFIG_STACKTRACE.

Link: http://lkml.kernel.org/r/51E3B3A2.8080609@huawei.com

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-07-15 12:38:10 -04:00
Paul Gortmaker
0db0628d90 kernel: delete __cpuinit usage from all core kernel files
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

This removes all the uses of the __cpuinit macros from C files in
the core kernel directories (kernel, init, lib, mm, and include)
that don't really have a specific maintainer.

[1] https://lkml.org/lkml/2013/5/20/589

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-07-14 19:36:59 -04:00
Paul Gortmaker
49fb4c6290 rcu: delete __cpuinit usage from all rcu files
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

This removes all the drivers/rcu uses of the __cpuinit macros
from all C files.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@freedesktop.org>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-07-14 19:36:58 -04:00
Liu ShuoX
e5248a111b PM / Sleep: avoid 'autosleep' in shutdown progress
Prevent automatic system suspend from happening during system
shutdown by making try_to_suspend() check system_state and return
immediately if it is not SYSTEM_RUNNING.

This prevents the following breakage from happening (scenario from
Zhang Yanmin):

 Kernel starts shutdown and calls all device driver's shutdown
 callback.  When a driver's shutdown is called, the last wakelock is
 released and suspend-to-ram starts.  However, as some driver's shut
 down callbacks already shut down devices and disabled runtime pm,
 the suspend-to-ram calls driver's suspend callback without noticing
 that device is already off and causes crash.

[rjw: Changelog]
Signed-off-by: Liu ShuoX <shuox.liu@intel.com>
Cc: 3.5+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-15 01:31:37 +02:00
Linus Torvalds
41d9884c44 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more vfs stuff from Al Viro:
 "O_TMPFILE ABI changes, Oleg's fput() series, misc cleanups, including
  making simple_lookup() usable for filesystems with non-NULL s_d_op,
  which allows us to get rid of quite a bit of ugliness"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  sunrpc: now we can just set ->s_d_op
  cgroup: we can use simple_lookup() now
  efivarfs: we can use simple_lookup() now
  make simple_lookup() usable for filesystems that set ->s_d_op
  configfs: don't open-code d_alloc_name()
  __rpc_lookup_create_exclusive: pass string instead of qstr
  rpc_create_*_dir: don't bother with qstr
  llist: llist_add() can use llist_add_batch()
  llist: fix/simplify llist_add() and llist_add_batch()
  fput: turn "list_head delayed_fput_list" into llist_head
  fs/file_table.c:fput(): add comment
  Safer ABI for O_TMPFILE
2013-07-14 11:42:26 -07:00
Al Viro
786e1448d9 cgroup: we can use simple_lookup() now
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-07-14 17:50:23 +04:00
Linus Torvalds
f8acc450e1 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Thomas Gleixner:
 "Fix a potential deadlock versus hrtimers"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix HRTICK
2013-07-13 15:37:57 -07:00
Linus Torvalds
505608d2b9 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq updates from Thomas Gleixner:
 - core fix for missing round up in the generic irq chip implementation
 - new irq chip for MOXA SoCs
 - a few fixes and cleanups in the irqchip drivers

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip: Add support for MOXA ART SoCs
  genirq: generic chip: Use DIV_ROUND_UP to calculate numchips
  irqchip: nvic: Fix wrong num_ct argument for irq_alloc_domain_generic_chips()
  irqchip: sun4i: Staticize sun4i_irq_ack()
  irqchip: vt8500: Staticize local symbols
2013-07-13 15:37:30 -07:00
Linus Torvalds
0da2736686 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
 - watchdog fixes for full dynticks
 - improved debug output for full dynticks
 - remove an obsolete full dynticks check
 - two ARM SoC clocksource drivers for sharing across SoCs
 - tick broadcast fix for CPU hotplug

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick: broadcast: Check broadcast mode on CPU hotplug
  clocksource: arm_global_timer: Add ARM global timer support
  clocksource: Add Marvell Orion SoC timer
  nohz: Remove obsolete check for full dynticks CPUs to be RCU nocbs
  watchdog: Boot-disable by default on full dynticks
  watchdog: Rename confusing state variable
  watchdog: Register / unregister watchdog kthreads on sysctl control
  nohz: Warn if the machine can not perform nohz_full
2013-07-13 15:36:09 -07:00
Linus Torvalds
560ae37178 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Thomas Gleixner:
 - fix for do_div() abuse on x86
 - locking fix in perf core
 - a pile of (build) fixes and cleanups in perf tools

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  perf/x86: Fix incorrect use of do_div() in NMI warning
  perf: Fix perf_lock_task_context() vs RCU
  perf: Remove WARN_ON_ONCE() check in __perf_event_enable() for valid scenario
  perf: Clone child context from parent context pmu
  perf script: Fix broken include in Context.xs
  perf tools: Fix -ldw/-lelf link test when static linking
  perf tools: Revert regression in configuration of Python support
  perf tools: Fix perf version generation
  perf stat: Fix per-socket output bug for uncore events
  perf symbols: Fix vdso list searching
  perf evsel: Fix missing increment in sample parsing
  perf tools: Update symbol_conf.nr_events when processing attribute events
  perf tools: Fix new_term() missing free on error path
  perf tools: Fix parse_events_terms() segfault on error path
  perf evsel: Fix count parameter to read call in event_format__new
  perf tools: fix a typo of a Power7 event name
  perf tools: Fix -x/--exclude-other option for report command
  perf evlist: Enhance perf_evlist__start_workload()
  perf record: Remove -f/--force option
  perf record: Remove -A/--append option
  ...
2013-07-13 15:35:47 -07:00
Linus Torvalds
4fa109b130 Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core locking updates from Thomas Gleixner:
 "Header cleanup as requested by Linus"

(This is the "don't include support for ww_mutex in a header file that
everybody wants, when almost nobody wants the ww part" change)

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  mutex: Move ww_mutex definitions to ww_mutex.h
2013-07-13 15:35:12 -07:00
Linus Torvalds
d144746478 Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
Pull MIPS updates from Ralf Baechle:
 "MIPS updates:

   - All the things that didn't make 3.10.
   - Removes the Windriver PPMC platform.  Nobody will miss it.
   - Remove a workaround from kernel/irq/irqdomain.c which was there
     exclusivly for MIPS.  Patch by Grant Likely.
   - More small improvments for the SEAD 3 platform
   - Improvments on the BMIPS / SMP support for the BCM63xx series.
   - Various cleanups of dead leftovers.
   - Platform support for the Cavium Octeon-based EdgeRouter Lite.

  Two large KVM patchsets didn't make it for this pull request because
  their respective authors are vacationing"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (124 commits)
  MIPS: Kconfig: Add missing MODULES dependency to VPE_LOADER
  MIPS: BCM63xx: CLK: Add dummy clk_{set,round}_rate() functions
  MIPS: SEAD3: Disable L2 cache on SEAD-3.
  MIPS: BCM63xx: Enable second core SMP on BCM6328 if available
  MIPS: BCM63xx: Add SMP support to prom.c
  MIPS: define write{b,w,l,q}_relaxed
  MIPS: Expose missing pci_io{map,unmap} declarations
  MIPS: Malta: Update GCMP detection.
  Revert "MIPS: make CAC_ADDR and UNCAC_ADDR account for PHYS_OFFSET"
  MIPS: APSP: Remove <asm/kspd.h>
  SSB: Kconfig: Amend SSB_EMBEDDED dependencies
  MIPS: microMIPS: Fix improper definition of ISA exception bit.
  MIPS: Don't try to decode microMIPS branch instructions where they cannot exist.
  MIPS: Declare emulate_load_store_microMIPS as a static function.
  MIPS: Fix typos and cleanup comment
  MIPS: Cleanup indentation and whitespace
  MIPS: BMIPS: support booting from physical CPU other than 0
  MIPS: Only set cpu_has_mmips if SYS_SUPPORTS_MICROMIPS
  MIPS: GIC: Fix gic_set_affinity infinite loop
  MIPS: Don't save/restore OCTEON wide multiplier state on syscalls.
  ...
2013-07-13 14:52:21 -07:00
Peter Zijlstra
971ee28cbd sched: Fix HRTICK
David reported that the HRTICK sched feature was borken; which was enough
motivation for me to finally fix it ;-)

We should not allow hrtimer code to do softirq wakeups while holding scheduler
locks. The hrtimer code only needs this when we accidentally try to program an
expired time. We don't much care about those anyway since we have the regular
tick to fall back to.

Reported-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130628091853.GE29209@dyad.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-12 13:52:58 +02:00
Stephen Boyd
a272dcca18 tick: broadcast: Check broadcast mode on CPU hotplug
On ARM systems the dummy clockevent is registered with the cpu
hotplug notifier chain before any other per-cpu clockevent. This
has the side-effect of causing the dummy clockevent to be
registered first in every hotplug sequence. Because the dummy is
first, we'll try to turn the broadcast source on but the code in
tick_device_uses_broadcast() assumes the broadcast source is in
periodic mode and calls tick_broadcast_start_periodic()
unconditionally.

On boot this isn't a problem because we typically haven't
switched into oneshot mode yet (if at all). During hotplug, if
the broadcast source isn't in periodic mode we'll replace the
broadcast oneshot handler with the broadcast periodic handler and
start emulating oneshot mode when we shouldn't. Due to the way
the broadcast oneshot handler programs the next_event it's
possible for it to contain KTIME_MAX and cause us to hang the
system when the periodic handler tries to program the next tick.
Fix this by using the appropriate function to start the broadcast
source.

Reported-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Mark Rutland <Mark.Rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: ARM kernel mailing list <linux-arm-kernel@lists.infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joseph Lo <josephl@nvidia.com>
Link: http://lkml.kernel.org/r/20130711140059.GA27430@codeaurora.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-07-12 12:35:40 +02:00
Thomas Gleixner
f2006e2739 Merge branch 'linus' into timers/urgent
Get upstream changes so we can apply fixes against them

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-07-12 12:34:42 +02:00
Maarten Lankhorst
1b375dc307 mutex: Move ww_mutex definitions to ww_mutex.h
Move the definitions for wound/wait mutexes out to a separate
header, ww_mutex.h. This reduces clutter in mutex.h, and
increases readability.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Dave Airlie <airlied@gmail.com>
Link: http://lkml.kernel.org/r/51D675DC.3000907@canonical.com
[ Tidied up the code a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-12 12:07:46 +02:00
Peter Zijlstra
058ebd0eba perf: Fix perf_lock_task_context() vs RCU
Jiri managed to trigger this warning:

 [] ======================================================
 [] [ INFO: possible circular locking dependency detected ]
 [] 3.10.0+ #228 Tainted: G        W
 [] -------------------------------------------------------
 [] p/6613 is trying to acquire lock:
 []  (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
 []
 [] but task is already holding lock:
 []  (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
 []
 [] which lock already depends on the new lock.
 []
 [] the existing dependency chain (in reverse order) is:
 []
 [] -> #4 (&ctx->lock){-.-...}:
 [] -> #3 (&rq->lock){-.-.-.}:
 [] -> #2 (&p->pi_lock){-.-.-.}:
 [] -> #1 (&rnp->nocb_gp_wq[1]){......}:
 [] -> #0 (rcu_node_0){..-...}:

Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.

Therefore solve it by making the entire RCU read side non-preemptible.

Also pull out the retry from under the non-preempt to play nice with RT.

Reported-by: Jiri Olsa <jolsa@redhat.com>
Helped-out-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-12 11:11:09 +02:00
Jiri Olsa
06f417968b perf: Remove WARN_ON_ONCE() check in __perf_event_enable() for valid scenario
The '!ctx->is_active' check has a valid scenario, so
there's no need for the warning.

The reason is that there's a time window between the
'ctx->is_active' check in the perf_event_enable() function
and the __perf_event_enable() function having:

  - IRQs on
  - ctx->lock unlocked

where the task could be killed and 'ctx' deactivated by
perf_event_exit_task(), ending up with the warning below.

So remove the WARN_ON_ONCE() check and add comments to
explain it all.

This addresses the following warning reported by Vince Weaver:

[  324.983534] ------------[ cut here ]------------
[  324.984420] WARNING: at kernel/events/core.c:1953 __perf_event_enable+0x187/0x190()
[  324.984420] Modules linked in:
[  324.984420] CPU: 19 PID: 2715 Comm: nmi_bug_snb Not tainted 3.10.0+ #246
[  324.984420] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[  324.984420]  0000000000000009 ffff88043fce3ec8 ffffffff8160ea0b ffff88043fce3f00
[  324.984420]  ffffffff81080ff0 ffff8802314fdc00 ffff880231a8f800 ffff88043fcf7860
[  324.984420]  0000000000000286 ffff880231a8f800 ffff88043fce3f10 ffffffff8108103a
[  324.984420] Call Trace:
[  324.984420]  <IRQ>  [<ffffffff8160ea0b>] dump_stack+0x19/0x1b
[  324.984420]  [<ffffffff81080ff0>] warn_slowpath_common+0x70/0xa0
[  324.984420]  [<ffffffff8108103a>] warn_slowpath_null+0x1a/0x20
[  324.984420]  [<ffffffff81134437>] __perf_event_enable+0x187/0x190
[  324.984420]  [<ffffffff81130030>] remote_function+0x40/0x50
[  324.984420]  [<ffffffff810e51de>] generic_smp_call_function_single_interrupt+0xbe/0x130
[  324.984420]  [<ffffffff81066a47>] smp_call_function_single_interrupt+0x27/0x40
[  324.984420]  [<ffffffff8161fd2f>] call_function_single_interrupt+0x6f/0x80
[  324.984420]  <EOI>  [<ffffffff816161a1>] ? _raw_spin_unlock_irqrestore+0x41/0x70
[  324.984420]  [<ffffffff8113799d>] perf_event_exit_task+0x14d/0x210
[  324.984420]  [<ffffffff810acd04>] ? switch_task_namespaces+0x24/0x60
[  324.984420]  [<ffffffff81086946>] do_exit+0x2b6/0xa40
[  324.984420]  [<ffffffff8161615c>] ? _raw_spin_unlock_irq+0x2c/0x30
[  324.984420]  [<ffffffff81087279>] do_group_exit+0x49/0xc0
[  324.984420]  [<ffffffff81096854>] get_signal_to_deliver+0x254/0x620
[  324.984420]  [<ffffffff81043057>] do_signal+0x57/0x5a0
[  324.984420]  [<ffffffff8161a164>] ? __do_page_fault+0x2a4/0x4e0
[  324.984420]  [<ffffffff8161665c>] ? retint_restore_args+0xe/0xe
[  324.984420]  [<ffffffff816166cd>] ? retint_signal+0x11/0x84
[  324.984420]  [<ffffffff81043605>] do_notify_resume+0x65/0x80
[  324.984420]  [<ffffffff81616702>] retint_signal+0x46/0x84
[  324.984420] ---[ end trace 442ec2f04db3771a ]---

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373384651-6109-2-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-12 11:11:01 +02:00
Jiri Olsa
734df5ab54 perf: Clone child context from parent context pmu
Currently when the child context for inherited events is
created, it's based on the pmu object of the first event
of the parent context.

This is wrong for the following scenario:

  - HW context having HW and SW event
  - HW event got removed (closed)
  - SW event stays in HW context as the only event
    and its pmu is used to clone the child context

The issue starts when the cpu context object is touched
based on the pmu context object (__get_cpu_context). In
this case the HW context will work with SW cpu context
ending up with following WARN below.

Fixing this by using parent context pmu object to clone
from child context.

Addresses the following warning reported by Vince Weaver:

[ 2716.472065] ------------[ cut here ]------------
[ 2716.476035] WARNING: at kernel/events/core.c:2122 task_ctx_sched_out+0x3c/0x)
[ 2716.476035] Modules linked in: nfsd auth_rpcgss oid_registry nfs_acl nfs locn
[ 2716.476035] CPU: 0 PID: 3164 Comm: perf_fuzzer Not tainted 3.10.0-rc4 #2
[ 2716.476035] Hardware name: AOpen   DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BI2
[ 2716.476035]  0000000000000000 ffffffff8102e215 0000000000000000 ffff88011fc18
[ 2716.476035]  ffff8801175557f0 0000000000000000 ffff880119fda88c ffffffff810ad
[ 2716.476035]  ffff880119fda880 ffffffff810af02a 0000000000000009 ffff880117550
[ 2716.476035] Call Trace:
[ 2716.476035]  [<ffffffff8102e215>] ? warn_slowpath_common+0x5b/0x70
[ 2716.476035]  [<ffffffff810ab2bd>] ? task_ctx_sched_out+0x3c/0x5f
[ 2716.476035]  [<ffffffff810af02a>] ? perf_event_exit_task+0xbf/0x194
[ 2716.476035]  [<ffffffff81032a37>] ? do_exit+0x3e7/0x90c
[ 2716.476035]  [<ffffffff810cd5ab>] ? __do_fault+0x359/0x394
[ 2716.476035]  [<ffffffff81032fe6>] ? do_group_exit+0x66/0x98
[ 2716.476035]  [<ffffffff8103dbcd>] ? get_signal_to_deliver+0x479/0x4ad
[ 2716.476035]  [<ffffffff810ac05c>] ? __perf_event_task_sched_out+0x230/0x2d1
[ 2716.476035]  [<ffffffff8100205d>] ? do_signal+0x3c/0x432
[ 2716.476035]  [<ffffffff810abbf9>] ? ctx_sched_in+0x43/0x141
[ 2716.476035]  [<ffffffff810ac2ca>] ? perf_event_context_sched_in+0x7a/0x90
[ 2716.476035]  [<ffffffff810ac311>] ? __perf_event_task_sched_in+0x31/0x118
[ 2716.476035]  [<ffffffff81050dd9>] ? mmdrop+0xd/0x1c
[ 2716.476035]  [<ffffffff81051a39>] ? finish_task_switch+0x7d/0xa6
[ 2716.476035]  [<ffffffff81002473>] ? do_notify_resume+0x20/0x5d
[ 2716.476035]  [<ffffffff813654f5>] ? retint_signal+0x3d/0x78
[ 2716.476035] ---[ end trace 827178d8a5966c3d ]---

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-12 11:10:47 +02:00
Linus Torvalds
c72bb31691 The majority of the changes here are cleanups for the large changes that
were added to 3.10, which includes several bug fixes that have been
 marked for stable.
 
 As for new features, there were a few, but nothing to write to LWN about.
 These include:
 
 New function trigger called "dump" and "cpudump" that will cause
 ftrace to dump its buffer to the console when the function is called.
 The difference between "dump" and "cpudump" is that "dump" will dump
 the entire contents of the ftrace buffer, where as "cpudump" will only
 dump the contents of the ftrace buffer for the CPU that called the function.
 
 Another small enhancement is a new sysctl switch called "traceoff_on_warning"
 which, when enabled, will disable tracing if any WARN_ON() is triggered.
 This is useful if you want to debug what caused a warning and do not
 want to risk losing your trace data by the ring buffer overwriting the
 data before you can disable it. There's also a kernel command line
 option that will make this enabled at boot up called the same thing.
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Merge tag 'trace-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing changes from Steven Rostedt:
 "The majority of the changes here are cleanups for the large changes
  that were added to 3.10, which includes several bug fixes that have
  been marked for stable.

  As for new features, there were a few, but nothing to write to LWN
  about.  These include:

  New function trigger called "dump" and "cpudump" that will cause
  ftrace to dump its buffer to the console when the function is called.
  The difference between "dump" and "cpudump" is that "dump" will dump
  the entire contents of the ftrace buffer, where as "cpudump" will only
  dump the contents of the ftrace buffer for the CPU that called the
  function.

  Another small enhancement is a new sysctl switch called
  "traceoff_on_warning" which, when enabled, will disable tracing if any
  WARN_ON() is triggered.  This is useful if you want to debug what
  caused a warning and do not want to risk losing your trace data by the
  ring buffer overwriting the data before you can disable it.  There's
  also a kernel command line option that will make this enabled at boot
  up called the same thing"

* tag 'trace-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (34 commits)
  tracing: Make tracing_open_generic_{tr,tc}() static
  tracing: Remove ftrace() function
  tracing: Remove TRACE_EVENT_TYPE enum definition
  tracing: Make tracer_tracing_{off,on,is_on}() static
  tracing: Fix irqs-off tag display in syscall tracing
  uprobes: Fix return value in error handling path
  tracing: Fix race between deleting buffer and setting events
  tracing: Add trace_array_get/put() to event handling
  tracing: Get trace_array ref counts when accessing trace files
  tracing: Add trace_array_get/put() to handle instance refs better
  tracing: Protect ftrace_trace_arrays list in trace_events.c
  tracing: Make trace_marker use the correct per-instance buffer
  ftrace: Do not run selftest if command line parameter is set
  tracing/kprobes: Don't pass addr=ip to perf_trace_buf_submit()
  tracing: Use flag buffer_disabled for irqsoff tracer
  tracing/kprobes: Turn trace_probe->files into list_head
  tracing: Fix disabling of soft disable
  tracing: Add missing syscall_metadata comment
  tracing: Simplify code for showing of soft disabled flag
  tracing/kprobes: Kill probe_enable_lock
  ...
2013-07-11 09:02:09 -07:00
Linus Torvalds
75fcf64dc7 Merge branch 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull printk locking fix from Thomas Gleixner:
 "A single lock ordering fix in the printk code"

* 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  printk: Fix rq->lock vs logbuf_lock unlock lock inversion
2013-07-10 18:14:24 -07:00